Investigation of the (pn) reacton on tin isotopes

Mechanism of the (pn) reaction on sup(117, 119, 120, 122)Sn isotopes in the Esub(p)=6-9 MeV range of proton energy is investigated. Neutron spectra (NS) are measured at the step of 1 MeV for angles of neutron escape equal to 30, 60, 90, 120 and 150 deg. Double differential cross sections, differential cross sections, total cross sections and angular distributions (AD) of neutrons for the assigned energy range are determineO. Energy NS from the 122Sn(pn)122Sb reaction at Esub(p)=6 and 9 MeV and angles of 30, 90 and 150 deg are given as an example. values of parameters of nuclear level densities of all the studied isotopes, relations of their inertial momenta to the solid-body value as well as total cross sections of (pn) reaction on 117Sn, 119Sn, 120Sn and 122Sn are tabulated. Dependence of CNS form on the angle of escape is observed with increase of proton energy Esub(p). The form of neutron AD depends on mass number of the isotope, Esub(p), neutron energy. The heavier isotope and higher Esub(p) are, the more noticeable is anisotropy. Analysis of the form of energy spectrum and neutron AD testifies to the fact that non-equilibrium processes manifest and become noticeable on the background of the reaction mechanism through the compound nucleus in this energy range. Quantitative estimation of the contribution of non-equilibrium processes is conducted. The obtained total cross sections are noted to be close to the calculation by the optical model